Steam vents for cookware

Abstract

A steam vent arrangement comprises a pan lid knob that incorporates a rotatable member that carries a slidable plunger. The plunger is moved by an SMA element to allow steam to vent via the knob and an aperture in a lid of the pan.

We claim: 
     
       1. A steam vent arrangement for a closable cooking utensil which has a lid, the arrangement comprising a body that forms a lifting knob for the lid which has a base that fits against a top surface of the lid, a manually rotatable member having two operative positions that fits inside the body, the member being shaped to open and close off a steam passageway through the body according to the rotational position of the member, a slidable plunger supported by and movable with the rotatable member that serves to close off the passageway when required, and an activator formed of shaped memory alloy material that automatically slides the plunger to open the passageway to allow steam to escape through the body to atmosphere when the temperature in the utensil rises to a predetermined value. 
     
     
       2. A steam vent arrangement according to claim 1, in which the rotatable member has an integrally formed upstanding flag that enables it to be manually rotated and in use visually indicates its relative rotation position within the body. 
     
     
       3. A steam vent arrangement according to claim 1, in which the body is formed with an integrally formed centrally offset downward extending stud arranged to locate in an aperture in the lid to prevent rotation of the body relative to the lid. 
     
     
       4. A steam vent arrangement according to claim 1, including an integrally formed threaded hole in the base of the body arranged to receive a securing screw that extends through the lid for holding the body to the lid.